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Geological T h <br /> Technics Inc Page 2 <br /> George's Service <br /> Report-Subsurface Investigation <br /> Project No 2812 <br /> August 11, 1995 <br /> 1.2 Monitoring Well Installation <br /> To further investigate the extent of gasoline range petroleum hydrocarbons in the <br /> soil and groundwater environments, Geological Technics Inc supervised the <br /> installation of three groundwater monitoring wells (MW-1, 2, & 3) in positions <br /> surrounding the suspected point of release (Figure 2 Site Map) <br /> The well borings were advanced to a total depth of 20 feet below surface grade using <br /> a 8 00 inch outside diameter continuous flight hollow stem auger owned and <br /> operated by V&W Drilling (C57# 658786) Soil cuttings underlain and covered with <br /> plastic <br /> The three 2 inch diameter wells were constructed of flush threaded schedule 40 PVC <br /> I casing with 15 feet of 0 010 inch perforations A #3 Monterey sand surrounded and <br /> extended one foot above the perforations The wells were surged using a surge <br /> block to settle the filter pack before the granular bentonite transition seal was <br /> installed and hydrated The annulus was sealed using a neat cement grout installed <br /> with a slurry pump and tremie pipe The wells were completed with a locking <br /> water tight cap enclosed in a flush mounted water tight traffic box The annular seal <br /> was completed integral with the installation of the well box The well top of casing <br /> measuring points were surveyed by a licensed land surveyor An as-built <br /> monitoring well construction schematic is attached as Figure 4 <br /> After the well sealingmaterials had set fora period eater than 24 h <br /> ( p gr ours), the well <br /> was developed (using mechanical surging and pumping methods) until a clear <br /> stream of water was obtained All development water was containerized in 55 <br /> gallon DOT approved containers and stored on site <br /> 1.3 Soil Sampling, Geologic Logging, and Subjective Observation <br /> Soil samples were collected for geological and analytical evaluation at five foot <br /> intervals A boring log providing sediment description using the U S C S and field <br /> observations was maintained by a professional geologist working under the <br /> supervision of a registered geologist Soil samples were collected in 6 0 inch brass <br /> liners using a 2 0 inch modified California split spoon sampler In the case of hand <br /> auger borings, samples were collected by driving a 2 0 inch stainless steel drive <br /> sampler equipped with a brass liner into undisturbed sediments All soil samples <br /> were sealed with Teflon or aluminum foil, capped, labeled and placed in a cooler <br /> with crushed ice at 4° Celsius for transport to the laboratory following Chain of <br /> Custody protocol <br />